Efficient biomass utilization for power, cooling, and hydrogen: A multi-generation approach with environmental and economic assessment

Abstract

The development of efficient and environmentally friendly biomass utilization methods for power generation remains a critical area of research. This study proposes an innovative multigeneration system centered on a biomass-fueled solid oxide fuel cell (SOFC). The configuration efficiently recovers waste heat by integrating an organic flash cycle, an ejector refrigeration cycle, and an organic Rankine cycle, alongside an electrolyzer to produce power, cooling, and hydrogen. The system's performance is comprehensively analyzed from thermodynamic, economic, and environmental perspectives. Optimal operating conditions are identified through a triple-objective optimization framework. The results reveal that the heat exchangers within the gasifier-SOFC integration are the primary sources of exergy destruction. Moreover, heat exchangers and electrolyzers are the largest contributors to the system's costs and environmental impact due to their exergy inefficiencies. The study determines the optimal fuel cell current density to be 5546 A/m², beyond which system performance declines significantly. Under optimal conditions, the product costs and environmental impact rate are approximately $12.06 per hour and 31.1 mPts/s, respectively. The system achieves an exergetic efficiency of 32.56 %, a payback period of 2.26 years, and a net present value of $2.56 million. These findings underscore the potential of the proposed multigeneration system to enhance efficiency, reduce costs, and minimize environmental impact, offering a promising solution for sustainable biomass utilization.